The present invention relates to an electric motor with an attached tachogenerator or tachometer whose rpm sensor, which preferably is configured as an annular permanent magnet, rotates together with the rotatable output shaft of the motor and charges a stationary detector, preferably an annular coil.
Motors of this type are required to be manufactured in many different structural sizes for a multitude of applications where control of the rpm of the motor is required. Often, the motors are used under conditions which necessitate dust and/or liquid tight encapsulation of the motor. The positioning of the tachogenerator within the encapsulation of the motor is often not possible due to the lack of space therein, and often the construction of a special, expensively manufactured motor housing of correspondingly larger volume is required. This is a drawback particularly in those cases in which motors of a certain type are manufactured with and without a tachogenerator.